Air brake for trains



El M. CAVANAGH Y* ET AL July 17, 1923.

AIR BRAKE FOR TRAINS 4 Sheets-Sheet l Filed Feb. 7, '1922 July 17, 1923.

E. M. CAVANAGH ET AL AIR BRAKE FOR TRINS Filed Feb. '7, 1922 4 Sheets-Sheet 2 Y 1am M @Wm R CPN 0 mmw m :www V. mw

amnlnllulwllm-H .ly l?, 1923.

E. M. CAVANGH ET AL.

AIR BRAKE FOR TRAINS Filed Feb. '7, 1922 4 Sheets-Sheet 5 .QN 1 MN. f f 1, NN Illy I @N I Nw ATTORNEY Julyw, 1923. 1,461,968'

E. M. CAVANAGH ET AL l AIR BRAKE FOR TRAINS Filed Feb. v. 192,2 4 sheets-Shelly;

I n v s Edward/z Cammy/z,

JPoEM/flane,

INVENTORS.

ATTORNEV Patented duly l?, 1923 il i EDWARD M. CAVANAGI-I AND ROBERT hatltt F l Q D E. TCFARLANE, 0F OTTLVA, ONTARIO,

CANADA.

AIR BRAKE Application filed February To all whom t 'may concern.'

Be it known that we, Emvann M. Cava- NAeH and llenar-ir E. McFimLarr, citizens ot the Dominion of Canada, and each a resident of Ottawa, in the county of Carleton and Province of Ontario, have invented certain new and useful Improvements in Air-Brakes i'for Trains, oit which the following is a specification.

rI`he present invention relates to automatic retainer valvesv for railway air brake system and the principal object is to provide means, whereby the brakes are held set, until the auxiliary air reservoir is charged to maximum capacity.

Another object of the invention is to provide a device of the character described, by the use of which, the train is at all times under control and which will prevent the ruiming away of trains.

With these and other objects in view, the invention consists in the construction, conibination and arrangement of parts as will be hereinafter Afully described, illustrated in the accompanying drawings, and pointed out in the claim hereunto appended.

In the drawings:

Figure 1 is a side elevational view of an auxiliary air reservoir and triple valve of a train line with they automatic retainer valve attached thereto.

Fig, 2 is a longitudinal sectional view oi the auxiliary` air reservoir and triple control valve with the latter in full service position.

Fig. 3 is a longitudinal vertical sectional view of the brake cylinder and piston, with the brake rod in elevation. 7

Fig. l is a vertical section of the automatic retainer valve, and i Fig. 5 is a similar view of a modified form of automatic retainer valve.

Referring to the drawings like numerals designate like parts in the various drawings.

1n the air brake systems now in use, the engineer has no power toholdthe brakes set until the` auxiliary reservoir is fully charged and the automatic retainer takes the place of the manually operated retainer'.

As the improved retaining valve is adapted for att-achn'ient to the air brake apparatus in order to set the wheel brakes, until the auxiliary air reservoir is fully charged, a brieil description ot the operation of the brake mechanism will be given,

Arca TRAINS.y

v, 19s,.' serial no. 534,513?.

Figures land 2 illustrate an auxiliary reservoir 10 in which the air is stored :tor use in the brake cylinder 11 and its use is confined to the car on which vit is located.

A piston 12 is operated by the air presi sure trom the auxiliary cylinder 10 in apply-` ing the brakes, 13 is the release spring and in applying the brakes, the air enters the brake cylinder 11 and forces the piston 12 outwardly and resultantly the spring 13 is compressed. ln releasing the brake, the air leaves the brake cylinder 11 and the release spring 13 forces piston 12 back to release position as illustrated in Figure 3. 111 is the front cylinder head and the same acts as a guide for the sleeve 15, which encloses the pull rod 16 connected to the brake shoe actuating mechanism.

An auxiliary tube 17 extends through the auxiliary reservoir 10 `and connects the triple control valve 18 direct-*with the brake cylinder 11 and when the brake is released,

the brake cylinder air flows back through` the tube 17 and through the triple valve eX- lia-ust to the atmosphere in the manner more fully described.

A. pipe 19 is connected to the check valve casing 18 of the triple valve 18 and leads from the engine reservoir, not illustrated.`

The triple valve 18 consists of the cylinder cap 20, triple body 21, the slide valve22, movable with the main piston 24;, slide valve spring28 and the triple piston 24 having a suitable packing ring mounted thereon. A valve 25 is arranged below the slide valve 22 and controls the air :from the triple valve into the auxiliary tube 17 through ports 26 and 27. An emergency valve 28 has a seat 29 and a check valve 80 extends downwardly within the check valve casing 18', y

The triple'control valve 18 consists of two distinct mechanisms, firstly the triple piston 24, slide valve 22 and graduating valve 25 together with the stem 31 and spring 32, this mechanism being used in making service stops and releasing brakes, or what is known as the service part or" the t-riple.

T he ether mechanism comprises the emergency valve 28 and check valve 30, which latter are only used in an emergency application of the brakes, so no furtherdescription is necessary of the same, as this construction so far described vis already in operation.

The air passes from the branch pipe 19 into the lower sections 18 of thev triple valve 18 and flows through passages 33, 34, ports 35 and on `through the feed groove 36 into chamber 37- and thence through the retarding casing 38, which extends into the auxiliary reservoir 10. This casing 38 contains the retarding stem 39 and spring 40. The parts 39 and 40 govern the movement oi' the triple piston 24 and slide valve 22 between. the release and retarded piston. Then the pressure on the outer face of the piston 24 exceeds that of the inner side for example 3 pounds, theI tension of the retarding spring ,40 will be overcome and the triple piston 24 and slide valve 22 will be moved to rreleased position. As the auxiliary cyl-- inder iills pressure increases and the ditfe-rence of pressure on the. two faces of the piston equalizes, the retaroing stern 39 and spring 40 will return the piston and valve to full released position.

As will be4 understood, the air pressure in the ,triple valve 18 is the same as that of the auxiliary reservoir 10 and these pressures are lconstantly maintained by virtue oic equalization.`

Initially the auxiliary reservoir 10 carries `its maximum pressure, approximately 7() pounds and the triple valve likewise is under similar pressure. Resultant of even prese sure of air on bothsides of the triple piston 24, the latter is held on seat 41. However, there is a constant passage of air through the -feed groove 36 and this air passes inte the auxiliary reservoir 10 `and serves to maintainthe maximum pressure therein.

When the brakes are to be set, sufficient air pressure is exhausted through branch pipe 19 to the atmosphere. As the pressure on the trip-le valve outer side of the piston 24 is reduced, the said valve moves out until the knob 42 touches the, end oj vthe graduating stem 31, ater which further movement is prevented. The slide valve 22 has uncovered port 26V and the requisite pressure of air will flow through port 27 into the auxiliary tube 17. This air which passes through tube 17 forces back the push rod 16and applies the brakes. p

Then the brakes are to be released, air is first admitted. to the triple valve to restore the maximum pressure to the same to equaliZe with that of Athe auxiliary reservoir 10, and this pressure forces the piston 24 back to seat 41.4 A part of thisair equivalent to that Vexpanded v by the auxiliary reservoir flows past the piston 24, thereby restoring the maximum capacity of' the said reservoir.

As it is necessary tomaintain a maximum I'pressure of air in the auxiliary reservoir 10, as the same is constantly loosing its pressure through numerous breakings or stops, T have provided an attachment to the above de` scribed system which prevents the release of the brake cylinder until the air pressure in the auxiliary cylinder 10 has resumed normal.

In this connection, it may be stated that heretofore, the air released from thepbrake cylinders has passed back through tube 17 to a port in the triple valve 18 to the atmosphere.

That the danger of releasing` the brakes before the restoration of the maximum air pressure in the auxiliary reservoir 10 is manifest. For example, a heavy train is travelling on a roadbed Where numerous slow downs are occasioned due to diiferent or curves are encountered. The brakes are set and released a number of times, thereby lowering the pressure in the auxiliary reservoir 10, and not enough time has elapsed to restore the maximum pressure in the said reservoir. iz an abrupt stop is necessary, there is not enough air in the auxiliary reservoir 10 to function the brakes, therefore a wreck or possible derailment is liable to occur.

To overcome this defect, Iprovide, as" illustrated more particularly in VFigure 1 the following attachment which will now be described.

is yheretofore stated, the air pressure from the brake cylinder 11, is exhausted into the atmosphere through a port in the triple valve 18 when the brake is released. This port is tapped for an yelbow connection 44 to which is attached a pipe 45. This pipe has 'a union connection 46 with a pipe 47 which communicates with the automatic air retainer valve 48, the operation of which will later be more fully described. This Yvalve 48 comprises a cylindrical casing 49 having a centrally ydisposed wall 50, while the valve casing 49 extends in the saine plane, but -diametrically opposite to that of the extension 51. The casing 49 and extension 51a're formed with chambers 52 and 53, the former being relatively larger of the two. The caps 54 and 55 are formed with annular exteriorly threaded flanges 56 and 57 which are screwed into the open threaded ends 58 and 59 oi' the casing 49 and extension 51 Vof the retaining valve. The casing wall 5() is formed with a centrally disposed chamber 60 into which opens the vertical ports 61 and 62, the former opening into the atmosphere, while lthe latter communicates directly with the exhaust pipe 47. Likewise the casing wall 50 is provided with transverse bore 63 which inter.

sects the chamber 60 and slidably mounted in said bore 63 is a rod 64 the ends of which project within the side chambers 52 Vand 53.

Pistons 65 and 66 are connected to the ends `ifiezueee have central threaded openings in which are mounted the threaded ends of the pipes 69 and 70. Pipe 70 has elbow connection 71 with a pipe 72 which latter is joined by the union 78 with the brake pipe 19. Pipe 69 has elbow connection 74 and 75 with pipes 76 and 77. The pipe 77 `has a union connection 7 8 with a bleed cock 79 on oneside and communication with the auxiliary cylinder 10 on the other side. Pipes 80, 81 and 82 have elbow connections 88 and 84 and carry a second bleed coclr This bleed coclr therefore is connected by pipes 80, 81 and 82 to the union 46 on the exhaust pipe 47.

r1 tube 86 has its upper end beveled and its lower end seated in a counter-sink in the wall 50 of the retainer valve 418 and extends within. the central chamber 60. Thistube 86 communicates with port` 62 and pipe 17 through which the brake cylinder exhaust is passed.

The piston rod 611- has formed on its lower surface at the medial point, a valve 87, having a lower beveled surface 88. This valve 87 is adapted to normally seat upon the beveled upper end ot the tube 86. to prevent the escape of the brake cylinder exhaust through pipe 47 and tube 86.

.To illustrate the operation, the auxiliary reservoir 10 has its maximum air pressure and the piston 24 contacts with seat 411 of the triple valve. A reduction is .made by exhausting air from the triple valve 18 through the branch pipe 19. As the pressure in the triple valve 18 is reduced below that of the auxiliary reservoir 107 the piston 211 is moved to service position as illustrated in Figure 2. This operation moves the slide valve 22 and uncovers the port 26 allowing a quantity oi' air to pass through port 27 to the auxiliary tube 17. This air passes through the auxiliary tube 17 and forces piston 12 in the brake cylinder 11 outwardly, thus actuating the brake pull rod 16 to set the brakes. As the pressure in the auxiliary reservoir 10 has been reduced below that oit the triple valve and it is necessary to maintain the same at uniform pressure, air pressure will be induced through branch pipe 19 to the triple valve 18 and at the same time through pipes 72 and 70 to the automatic retaining valve 48. Meanwhile the piston 241 has returned to seat 411 and the port 26 is closed by the slide valve The induced air entering chamber 53 oit the retaining valve 418 forces the small piston 63 inwardly thereby movingr rod 64C and the valve 87 over the end of tube 86 to cover the same. The air from the brake cylinder 11 upon release of the brake, passes back through the tube 17 and into pipes 15 and f1.7 to tube 86, but its escape is 'blocked by the valve 87 on rod 64; in the retaining` valve. .151s heretofore stated, the exhaust in the ordinary air brake systems, is passed 'to attained, as follows. The pressure ol' air on the pistons 65 and 66 is unequaled as piston 65 has greater contact being larger than piston 66. The air from the cylinder 10 passes out through pipes 7 7-76 and 69 into the chamber 52 ot the retainer valve Z18 and forces `piston 65 outwardly, thus moving the stop valve 87 from over the tube 86 to allow the exhaust air from the brake cylinder' 'to pass through the retainer valve 48, through port 61 to the atmosphere. i

Upon the nex, air feed through branch. pipe 19, the piston 2a will be forced baelr to seat al, simultaneously with the forcing bacl of piston 66 in the retainer valve 18 to cause the valve 87 to cover the exhaust tube 86, to seal the exhaust. After another braking; operation, `the operation is repeated, but no exhaust can escape into the atmosphere a'lter a braking` operation until the reservoir 10 has itsmaximum pressure.

A pressure operated retainer valve 88 is connected to the exhaust pipe 47 which may be set in operation to only maintain a pressure of 15 pounds.

Pipe is the original exhaust or retainer pipe which is in operation at the present time. This pipe is provided with cutout cock which must be closed when automatic `retainer is being used.

.107 and 108.

Tt is obvious that after a reduction has been made in the train line. the retainer valve is in release position until the brakes are released. Whenthe pressure Jfor the train line comes in contact with the retainer valve it closes communication with the atmosphere and holds the brake set, until the auxiliary reservoir becomes fully charged.

Owing` to piston 65 having `larger Contact suri'ace than piston 66, the pressure 'from the auxiliary reservoir :forces thel same out .wardly and opens Communication to the etinosphere.

From the foregoing; it is thought that the Construction of my invention will be Clearly understood, and, therefore, a more extended explanation has been omitted.

What we elaini as new is:

In Combination with a railway air bralre system, pressure operated retainersI` pipe connections between the triple valve and controlling` valve. pipe connections between the auxiliary Cylinder and said controlling; valve, pipe connection between said control ling' 'valve and the regular train pipeline, said controlling` valve consisting of a head, cylinders formed in each end of said head, pistons reeiprocally positioned in said eylinders, a connecting piston rod between said pistons, an air ehaniber between said cylinders, anr intake*opening` 'from the rst said pipe connection, an exhaustopening from said air chamber, a Valve member carried by said piston rod to control said intake opening, said valve memberl consisting of ta* pered bloelr adapted to normally seat upen the beveled end oit' the pipe and to elose the first said pipe connection and to be Controlled by relative pressure of the air in the other said pipe connections on `said pistons. In testimony whereof we our signa-- tures inthe presence of two .Vitnes-ses.r

EDWARD M. QVANAGH. ROBT. E. B/[CFALLRLNFJ lfTJit-nesses:

M. MCMILLAN, EL SLoNnMsKY. 

